Jump to content

jshaw3

Members
 View Profile  See their activity

  • Posts

    6

  • Joined

  • Last visited

 Content Type 

Posts posted by jshaw3

    Sub-10 / Sub-12 / RPW-10 Repair Blog

    in Technical/Restorations

    Posted

    Has anybody actually adjusted the bias on a Sub10?

     

    My understanding was there are two pots side by side and they both needed to be adjusted. I replaced them both with new and when I went to adjust as I had seen in a video posted earlier, only one affected the output signal. I used the low signal inputs. Cleaned up the signal nicely, but I can't see where the other one does anything at all. Even tried it with a signal into left and right separately, but got the same result.

     

    Could the other pot be for the hi-input? That's about the only thing I didn't try!

     

    Any insight would certainly be appreciated.

     

    TIA....

     

    Sub-10 / Sub-12 / RPW-10 Repair Blog

    in Technical/Restorations

    Posted

    On 2/13/2022 at 9:51 AM, Bman0202 said:

    After alot more troubleshooting I narrowed it down to q9 and d17 on the "speaker -" rail. D17 was ultimately dropping too much voltage. Messing with q9.

     I measures the 15 volts going in but only 8volts was coming out. 

     

    Replaced and now its all good thank goodness. Clean waveform in and out. Adjusted the bias to make sure the wave form looks proper 

     

    Thanks tho this forum ive gotten it back up and running

     

    Can you tell us what you used to replace D17?

     

    Thanks

    Sub-10 / Sub-12 / RPW-10 Repair Blog

    in Technical/Restorations

    Posted

    Thanks for getting back to me.

     

    I have tracked down a suitable replacement but still trying to get this back to 100%. I have not been able to find a service manual or schematic anywhere for this. I'm getting ready to order components for the PDC board because my remaining problem seems to be coming from it, but apparently the 1N4140 diode is obsolete so I'm trying to find a suitable replacement. I see a posting here that substituted a 1N4148 (although I don't actually know if it works) and came across an NTE replacement !N5401 as well. Not sure if anyone can shed any more light on this.

×
×
  • Create New...